Air cooled light projector



Nov. 18, 1952 J. P. FOULDS AIR 000w) LIGHT PROJECTOR Filed June 22, 1950Inventor: John F. Foulcls,

W MW His Attorney.

Patented Nov. 18, 1952 UNITED STATES PATENT OFFICE AIR COOLED LIGHTPROJECTOR John P. Foulds, Revere, Mass., assignor to General ElectricCompany, a corporation of New York 3 Claims.

My invention relates to light projectors, and more particularly tocooling means for floodlighting projectors and the like.

It is a general object of my invention to provide means for appreciablyincreasing the energy output and wattage rating of light projectors,such as floodlights and the like, without increasing their physicalsize.

It is another object of my invention to provide new and improved airrecirculating and cooling means for floodlight projectors and the like.

It is a still further object of my invention to provide new and improvedmeans for evenly distributing generated heat in a floodlight projectorand the like, thereby to minimize critical hot spots and permit anincrease in rating.

My invention itself will be more fully understood and its variousobjects and advantages further appreciated by referring now to thefollowing detailed specification taken in conjunction with theaccompanying drawing, wherein Fig. 1 is a side elevational view, partlyin section, of a fioodlight projector embodyin my invention; Fig. 2 is afragmentary end elevational view of the projector shown at Fig. 1; andFig. 3 is a cross-sectional view taken along the line 3-3 of Fig. 1.

Referring now to the drawing in detail, I have shown a light projectorcomprising a divergent main reflector I' having a mounting collar 2, acup-shaped socket housing 3 fixed to the mounting collar, and an airrecirculating conduit 4 externally connecting the reflector l with theinterior of the collar 2. The entire projector is pivotally mountedbetween the side arms of a mounting yoke 5 by means of oppositelydisposed trunnions 2a projecting from the sides of the collar 2.

Apart from the air recirculating conduitv 4, the light projector shownin the drawing is generally similar to that described and claimed inPatent 2,327,820-Rogers. The main reflector I is generally conoidal inshape, having a narrow eccentric neck portion la and diverging toward awide mouth portion lb. The mouth portion of the reflector is closed by acover glass 6. The collar 2 is connected at one end to the neck portionla of the main reflector and closed at its other end by the sockethousing 3. The socket housing 3 is provided with a lamp socket 'l, andthe mounting collar 2 serves to encase the neck portion of anincandescent lamp 8 mounted in the socket 1. In the illustratedembodiment of the invention, the axis of the mounting collar 2 isdisposed at an obtuse angle with respect to the axis of the conoidalmain reflector I. The main reflector I, collar 2 and socket housing 3together thus constitute a closed casing which may be generally regardedas including a main reflector compartment on one side of the reflectorneck Ia, and a socket compartment on the other side.

Interiorly of the projector casing, and in the region of the mainreflector neck portion la, there is mounted a ring-shaped auxiliaryreflector 9 which extends generally across the neck portion of the mainreflector and serves as a dividing wall between the main reflectorcompartment and the socket compartment. The auxiliary reflector iscentrally apertured to accommodate the neck of the lamp 8, which extendsfrom the socket I, through collar 2 and the auxiliary reflector 9, intothe main reflector compartment. The ring-shaped auxiliary reflector 9 isradially spaced from the neck la of the main reflector I, thereby topermit passage of air from the socket compartment into the mainreflector compartment; and the auxiliary reflector is so shaped that airpassin from the socket compartment into the main reflector compartmentis directed into intimate contact with the bulb portion of the lamp 8and the closely adjacent main reflector areas. The reflector 9 issupported upon a plurality of mounting brackets- IU fixed upon bosses IIon the socket housing 3.

Externally of the closed casing constituted by the main reflector I, thecollar 2, and the socket housing 3, I provide an air cooling and returnconduit 4 including a finned recirculating pipe l2 and a fan housing l3.This air cooling conduit 4 is connected between the mouth portion lb ofthe main reflector l and the tubular mounting collar 2. Therecirculating pipe is connected at one end to the mouth portion lb ofthe main reflector and at the other end to the inlet side of the fancasing [3. The outlet side of the fan casing is connected to the collar2 at the side thereof, thereby to introduce air transversely into thesocket compartment and in a direction substantially perpendicular to theneck of the lamp 8, i. e., radially.

The recirculating pipe I2 is provided both interiorly and exteriorlywith cooling fins 12a, and is divided longitudinally into two sectionswhich are bolted together in the manner indicated at Fig. 3.

Within the fan housing l3 there is disposed a centrifugal blower l4driven by a motor IS. The

blower [4 draws air from the recirculating pipe [2 and exhausts it intothe socket compartment through the collar 2, so that air is continuouslycirculated from the socket compartment into the main reflectorcompartment and back through the air cooling conduit 4. Air traversingthis closed path is cooled in the recirculating pipe 12 and introducedinto the socket compartment transversely across the neck of the lamp 8.The air is then directed by the auxiliary reflector 9 into the mainreflector compartment in intimate contact with the bulb portion of thelamp 8 and the narrow reflector portion near the reflector neck. The airheated up in its passage through the socket and main reflectorcompartments is exhausted from the main reflector compartment into therecirculating pipe [2 for recooling. By this arrangement, the coolestair is introduced into the hottest part of the projector casing, and isdirected by the auxiliary reflector 9 into the most useful path in itspassage through the casing. The air thus passing at considerablevelocity through the closed projector casing serves to evenly distributethe heat within the casing,

thereby minimizing the generation of critical hot spots in theprojector. Moreover, the cooling is done by means of recirculated air,so that the entire system is sealed and closed to the atmosphere. Thisprevents the accumulation within the reflector casing of dust and dirtwhich would otherwise rapidly decrease the light projection efliciencyof the unit.

While I have described a preferred embodiment of my invention by way ofillustration, many modifications will occur to those skilled in the artand I, therefore, wish to have it understood that I intend in theappended claims to cover all such modifications as fall within the truespirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. In a light projector, a divergent main reflector having a narrow neckportion and a wide mouth portion provided with a light transmittingcover, enclosure means including a lamp socket housing and providing asocket compartment externally adjacent said neck portion of said mainreflector, said main reflector and said enclosure means constituting aclosed projector casing,

means including an air conduit external of said casing for circulatingair in a closed path from said socket compartment to said mouth portionof said reflector and back through said conduit, air from said conduitentering said socket compartment in a direction substantiallyperpendicular to the neck of a lamp mounted therein and in the regionthereof, and an annular auxiliary reflector mounted interiorly of saidcasing and partially closing the neck portion-of said main reflector,said auxiliarv reflector being apertured to accommodate the neck of alamp mounted in said socket housing and being shaped to direct ,air fromsaid socket compartment into said main reflector in intimate contactwith said lamp and main reflector.

2. In a light projector, a divergent main reflector having a narrow neckportion and a wide mouth portion provided with a light transmittingcover, a lamp socket housing and a mounting collar connected to saidneck portion and constituting with said main reflector a closedprojector casing, a ring-shaped auxiliary reflector disposed at the neckportion of said main reflector and dividing said casing into a mainreflector compartment and a socket compartment, said auxiliary reflectorbeing centrally apertured to accommodate the neck of a lamp extendingthrough said socket compartment and into said main reflector compartmentand being shaped to direct air from said socket compartment into saidmain reflector compartment in intimate contact with said lamp, an aircooling conduit external of said casing connecting said mouth portion ofsaid main reflector with said socket compartment, said conduit beingconnected to said mounting collar to introduce air into said socketcompartment in a direction substantially perpendicular to the neck ofsaid lamp, and a circulating fan for continuously recirculating air fromsaid socket compartment to said main reflector compartment and backthrough said cooling conduit.

3. In a light projector, a conoidal main reflector having a narrow neckportion and a wide mouth portion provided with a light transmittingcover, a tubular mounting collar fixed to said neck portion of said mainreflector with the axes of said collar and said main reflectorrelatively angularly disposed, a cup-shaped socket housing fixed to saidcollar and providing with said collar and main reflector a closedprojector casing. a ring-shaped auxiliary reflector mounted interiorlyof said casing across said neck portion of said main reflector anddividing said casing into a main reflector compartment and a socketcompartment, said auxiliary reflector being centrally apertured toaccommodate the neck of a lamp mounted in said socket housing andextending into said main reflector compartment and being shaped todirect air from said socket compartment into said main reflectorcompartment in intimate contact with said lamp, an air cooling conduitexternal of said casing connecting said mouth portion of said mainreflector with said mounting collar, said cooling conduit being connected to said collar to introduce air into said socket compartment in adirection substantially perpendicular to the neck of said lamp, and anair circulating fan mounted in said conduit continuously to circulateair from said socket compartment into said main reflector compartmentand back through said cooling conduit.

JOHN P. FOULDS.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,286,269 Foley Dec. 3, 19181,634,399 Dake July 5, 1927 1,681,153 Johnston Aug. 14, 1928 1,895,887Lorenz Jan. 31, 1933 1,905,811 Culver Apr. 25, 1933 2,288,345 De Vry eta1 June 30, 1942 2,295,863 Paradis Sept. 15, 1942 FOREIGN PATENTS NumberCountry Date 750,412 France May 22, 1933

